I'm back at JPL, serving as SOWG Chair planning Sol 57. The mission continues to go very well, with recent drives executed nearly perfectly. The rover is now positioned near a windblown ripple that is the current target of both scientific and engineering study. As I mentioned previously, we have been looking for a relatively fine-grained soil patch to scoop into CHIMRA, the "Collection and Handling for Interior Martian Rock Analysis" subsystem. CHIMRA will be used to sieve and portion samples into the CheMin and SAM instruments for mineralogic and organic chemical analysis. But before such samples will be delivered, some Martian soil will be used to clean any terrestrial contamination from CHIMRA by passing it through the system. So today's plan included the first "scuff" by one of the rover wheels, intended to measure the depth of the ripple and determine whether it is safe to scoop it. To scuff, the left front wheel will be rolled over the ripple, then that wheel will be rotated while the other 5 wheels are held stationary. This should allow a cross-section of the ripple to be imaged, and the composition of the interior of the ripple to be examined. After the scuff is complete, the rover will move back to essentially its current position to allow the arm to be used to place the MAHLI and APXS instruments into the scuffed area.